hi there Rminde! welcome to the forum and if you read this before you head off for your trip, HAVE A NICE TIME!

as for the summer make up tips you're looking for, well we've to keep in mind that the first things are to protect you from sun exposure and sweating.

i would advise a sunblock plus moisturizer, preferably a light one. but if you really have to wear foundation, then i'd advise to mix it with loose powder to make sure that you remain fresh-looking.
loose shimmer powders can also have a really nice effect when worn on the arms/neck, even for your night parties. and maybe opt for gloss, to keep it light and relaxed but still classy.

you might have to work on a tan, if you haven't already done it

your eye make up shouldn't be too heavy, work on your lashes rather.

i hope this helps! i tried to compact all this a bit in case you need the info urgently!